1. Field of the Invention
This invention relates to model implementation and more particularly relates to apparatuses, systems, and methods for combining theoretical and empirical knowledge as an improvement over a purely theoretical or purely empirical model.
2. Description of the Related Art
Modern diesel emissions regulations are driving engine manufacturers to use particulate filters in engine after treatment systems. These filters accumulate soot over time, and the soot must be removed from the filter periodically.
There are two primary mechanisms for removing the soot. The engine naturally generates some NO2 in the exhaust stream. At low temperatures, this NO2 oxidizes some of the soot on the filter, releasing the soot—typically as CO or CO2. This mechanism is called “noxidation.”
The noxidation mechanism is often insufficient to keep the particulate filter at acceptable soot levels. Therefore, a faster oxidation mechanism is sometimes required. One implementation of this mechanism is to raise the temperature of the exhaust stream to the point where simple O2 will oxidize the soot. This temperature is higher than where the engine will typically run under normal loads and therefore must generally be triggered intentionally by the engine controls. This mechanism is called “oxidation.”
In order to raise the temperature of the exhaust in order to trigger the “burn off” event, fuel may be injected into the exhaust stream and subsequently ignited. A dosing controller monitors the temperature and raises and lowers the temperature to ensure a proper burn off.
If the soot level is too high in the particulate filter when the oxidation or burn off event is initiated, oxidation can generate heat within the particulate filter much more quickly than the rate at which the heat can be dissipated. This causes local temperature spikes within the particulate filter, and can result in unnecessary wear on the particulate filter or even mechanical failure of the particulate filter. A runaway heat spike like this is called an “uncontrolled regeneration.”
In order to prevent these heat spikes, the dosing controller attempts to determine an average temperature in the particulate filter and control the exhaust such that the temperature of the exhaust remains within a range of this average temperature. However, the particulate filter often can handle temperatures much higher than the average temperature. A burn off at higher temperatures reduces the amount of time required for the burn off or oxidation event. Unfortunately, current after treatment control systems are unable to calculate or predict a target maximum temperature based upon the average temperature of the particulate filter.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that can overcome the limitations of current after treatment control systems. Beneficially, such an apparatus, system, and method would calculate a target maximum temperature based on an average particulate temperature.